Self locking contact plug



May 8, 1934.

C. A.v GOOD SELF LOCKING CONTACT PLUG Filed May 14, 1929 .rzj.

mmv'rox CHARLES ATTORNEY Patented May 8, 1934 SELF LOCKING CONTACT PLUG 5 Charles A. Good, San Franciscmflalif.

Application May 14, 1929, Serial No. 362,885

1 Claim.

Thisinvention relates to improvements in contact plugs such as are commonly used in electrically connecting irons, lamps and other elec' trical equipment with an electric current. Plugs of this type are generally held in place by the frictional engagement of the plug and contact parts are oftenwpulled out of contacting position when the conductor cords to which they are attached are pulled or jerked accidentally.

An object of the invention is to provide a contact plug of the character described which will be automatically locked against unintentional displacement when it is plugged into position to establish electrical connection of an iron, lamp, or other electrical equipment with a source of electric current.

Another object of the invention is to provide a contact plug 01 the character described which has a novel means thereon for quickly and easily releasing the plug at will.

smother object is to provide a plug of the character described which is simple and inexpensive as to construction, positive and reliable in operation and not appreciably increased as to size in spite of the provision of the novel locking means thereon.

A further object is to provide a plug of the character described in which a better contacting action is provided by reason of the locking means holding the contacts in close and tight interlock ing engagement.

The invention possesses other objects and features of advantage, some or which, with the -lore-= will be set forth in the following descrip= tion or the preferred form of the invention which is illustrated in the drawing accompanying and forming part oi the specification. lit is to be understood, however, that variations in the showing made by the said drawings and description be adopted within the scope oi the invention as set forth in the claim.

Referring to the drawing,

Figure l is a side elevation of the plug oi my invention shown as when in operative position with part thereof broken away and in section.

Figure 2 is a vertical section of a modified form of the'plug of the invention.

Figure 3 is a vertical sectional view of another modified form of the plug of the invention.

Figure l is'a fragmentary side elevation showing the coacting interlocking contact members.

"the embomment of my invention shown in the accompanying drawing comprises a plug body portion 7 formed of the usual complementary valves held together by the tastenings 3.

Contact members 9 and 10 are pivoted as at 11 within openings 12 provided in the body portion and have their inner'terminals disposed in inwardly spaced relation'to the center ends of said openings. Electrical conductors 13 are connected as at 14 with said contact member.

In the present instance there is shown in the drawing two contacts 15 and 16 such as would be carried on an electric iron or'other electrical element or device, designated 17, and with'which my plug is to be used. These contacts 15 and 16 will extend into the plug openings 12 in effecting the engagement therewith of the contacts 9 and 10.

Means is provided for automatically locking the contacts against unintentional displacement when they are engaged with one another as hereinbefore described. In other words, this means will lock the contacts together when the plug is plugged in. As'here shown, this means is provided by forming the center ends of the contacts 9 and 10 with lateral extensions 19 and providing coacting shoulders 20 on the contacts 15 and 16. These shoulders are formed at the inner terminals of guide grooves 21 provided in the contacts 15 i and 16. Springs 22 act to hold the contacts in position to readily engage in the groove 21 when the plug is moved to engage the contacts thereoi with the contacts 15 and 16. During this movement of the plug the free ends of the contacts *9 and 10 slide in the guide grooves to the points where the lateral extensions 19 move beyond the plane of the shoulders 20. At this time the springs 22 quickly move the contacts 9 and it so that aid extensions the shoulders 20 to thereby loci; the plug against unintentional displacement.

Means is provided for unlocking or releasing the plug. As here shown this means is operable on the side of the plug and comprises push buttons 2 and 25 slidably mounted on opposite sides of the body portion. The inner of these buttons engage with the contacts 9 and 10 and pushed inward move the contacts inward and dis pose the lateral ends 19 clear of the shoulder whereby the plug may be readily withdrawn.

it will be noted that the push buttons are disposed in a convenient position such that on grasp ing the plug to disengage it the button may be easily pushed in to release the plug.

While I have shown the plug as having both the contacts 9 and 10 and the contacts 15 and is arranged to interlock, I wish it understood that may embody the locking means in but one oi the contacts 9 or 10,'if desired. In either event the 19 will hook over and engage I locking means will prevent accidental displacement of the plug.

As shown in Figure 3, the invention is embodied in a plug having the contacts 31 and 32 projecting from the plug body 33. These contacts are pivoted as at 34 in openings 35 of said body and have the lateral extensions 36 or their outer ends as provided with the contacts 9 and 10. The same unlocking means is employed as in the other form of the invention and includes the push huttons here designated 37 and 38. The coacting I claim:

In an electric contact device, a body portion, contact members pivoted on the body portion, frictional interlocking means on the free ends of said contact members, other contact members mounted tor engagement with the first named contact members and having guide grooves thereJi in which the free ends of the first contact members slidably engage, locking shoulders on said other contact members with which said projections are moved into locking engagement from said grooves on the movement of the two sets of contacts into engagement with one another, springs acting to move the first named contacts to cause the locking projections to lockingly engage with said shoulders, and'push buttons slidably mounted on the body portion with their inner terminals engaged with said pivoted contacts and arranged to move the projections laterally out of locking position.

. CHARLES A. GOOD. 

